Mt St Helens - More than 400 earthquakes, yet no imminent eruption

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Mount St. Helens records more than 400 earthquakes since mid-July, but no signs of imminent eruption
https://apnews.com/article/how-many-earthquakes-mount-st-helens-621b5c405f4cf80c76ba68d10b2f5094

VANCOUVER, Wash. (AP) — More than 400 earthquakes have been detected beneath Washington’s Mount St. Helens in recent months, though there are no signs of an imminent eruption, according to the U.S. Geological Survey.

Most of the quakes over a three-month span beginning in mid-July were less than magnitude 1.0 and too small to be felt at the surface, the agency reported last week.
Maybe if the quakes were 2 or 3 Mag and increasing in strength, that would be a concern.

 
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Lets hope we don't have a repeat of 2004. It was fun being up there during the dome building eruption.
https://www.usgs.gov/volcanoes/mount-st.-helens/2004-2008-renewed-volcanic-activity
The sudden reawakening of Mount St. Helens in late September 2004 was surprising because the preceding four years had seen the fewest earthquakes since the 1980-86 eruption ended.

In the early hours of 23 September 2004, a swarm of small-magnitude (< 1), shallow earthquakes (< 1 km or about 0.5 mi below the surface) began beneath the 1980-1986 lava dome. Over the next seven days, earthquakefrequency and size increased and a growing welt formed on the SE margin of the 1980-86 lava dome and nearby portions of Crater Glacier. By September 26, 2004, the rise in activity led scientists to warn of an increased chance of explosions from the lava dome.

On October 1, 2004, the first of several explosions shot a plume of volcanic ash and gases into the atmosphere from a vent on the southwest margin of the growing welt. Four additional steam and ash explosions occurred through October 5th, and three produced noticeable fallout of fine ash downwind.

https://www.usgs.gov/media/videos/mount-st-helens-steam-ash-emissions-and-dome-growth-october-2004
 
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1. Why did Mt. St. Helens experience over 400 earthquakes without leading to an eruption?

The occurrence of more than 400 earthquakes around Mt. St. Helens is primarily due to the movement of magma and shifting of tectonic plates beneath the surface, which often leads to seismic activity. However, not all seismic activities result in eruptions. The earthquakes might simply indicate the repositioning of magma within the volcano without sufficient pressure or volume to cause an eruption.

2. How do scientists monitor Mt. St. Helens for potential eruptions?

Scientists use a variety of tools to monitor volcanic activity at Mt. St. Helens. These include seismographs to detect earthquakes, GPS instruments to measure ground deformation, gas sensors to detect changes in volcanic gases, and thermal imaging to observe changes in temperature on the volcano’s surface. This comprehensive monitoring helps predict potential eruptions and assess the volcano's behavior.

3. What does it mean when there is no imminent eruption despite numerous earthquakes?

No imminent eruption means that, based on current observations and data, there are no immediate signs that an eruption is likely to occur soon. Even though the volcano is experiencing earthquakes, other critical indicators such as significant ground deformation, substantial gas emissions, or increased heat flow, which typically precede an eruption, may not be present.

4. Can these earthquakes lead to other forms of geological activity?

Yes, earthquakes at a volcano like Mt. St. Helens can lead to other forms of geological activity such as rockfalls, landslides, or even minor surface cracks. These activities are typically localized around the volcano and are directly related to the movement of the earth's crust in that area.

5. What should residents near Mt. St. Helens do in response to these earthquakes?

Residents near Mt. St. Helens should stay informed through updates from local geological services like the US Geological Survey (USGS). It's important to have an emergency plan in place and be prepared for potential evacuation orders, even if an eruption is not immediately expected. Awareness and preparedness are key to safety in volcanic regions.

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